Refrigerant condenser arrangement



March 4, 1969 .1. P. NORTON REFRIGERANT CONDENSER ARRANGEMENT SheetFiled Jan. 24, 1967 p/HI INVENTOR. John 1? Norfan BY Mm March 4, 1969 J.P. NORTON 3,430,453

REFRIGERANT CONDENSER ARRANGEMENT Filed Jan. 24, 196? Sheet 2 0f2INVENTOR- Jo/vn 1 Maria/7 BYZMM United States Patent REFRIGERANTCONDENSER ARRANGEMENT John P. Norton, St. Louis, Mo., assignor toAmerican Air Filter Company, Inc., Louisville, Ky., a corporation ofDelaware Filed Jan. 24, 1967, Ser. No. 611,300

US. Cl. 62-196 Int. Cl. F!) 39/04, 41/00 4 Claims ABSTRACT OF THEDISCLOSURE Cross-refercnce to related applications The present inventionrelates, in part, to co-pending application Ser. No. 516,641 filed Feb.18, 1966 by Harold L. Kirk and John P. Norton, now Patent No. 3,365,133.

Background of the invention In refrigeration systems of the type where avaporizable-condensible refrigerant is circulated through a fluid flowcircuit including cooperatively connected compressor, condenser,expansion device, and evaporator, the pressure, temperature, and flowrate of refrigerant through the circuit are interrelated and affectsystem performance. This is because the refrigerant pressure at thecompressor outlet significantly influences the pressure at the inlet ofthe refrigerant expansion device so, for example, a decrease in pressuredecreases the rate of flow of refrigerant through the expansion deviceto substantially reduce the refrigerating capacity of the system.Furthermore, in such previous refrigeration systems the pressure of therefrigerant emitted from the condenser has been related to thetemperature of the cooling medium supplied to the condenser so anuncontrolled decrease in temperature of the cooling medium supplied tothe condenser results in reduced pressure in the refrigerant emittedfrom the condenser, and vice versa, regardless of the cooling demands onthe system.

Previous refrigeration systems have provided various complicated,expensive arrangements to maintain optimum compressor dischargepressure. One such previous arr-angement has included means to controlthe pressure of the refrigerant emitted from the compressor in responseto change in the temperature of the cooling medium supplied torefrigerant condenser while other arrangements have directly controlledcompressor discharge pressure regardless of refrigerant pressure at theexpansion device.

In other methods, heat is added to the refrigerant to selectivelyincrease the temperature, and pressure, of the refrigerant at thecompressor outlet or the temperature or flow rate of the cooling mediumsupplied to the refrigerant condensing means, for example ambient air,is regulated to control the temperature of the refrigerant within thecondenser.

In some cases, means have been provided to flood selected portions ofthe condenser with refrigerant in accordance with the pressure at theoutlet of the compressor to reduce the effective heat transfer area ofthe condenser and correspondingly decrease the heat loss by therefrigerant to increase refrigerant pressure. Such arrangements providesluggish control and response to change in conditions is slow becausethe condense-r must be drained or "ice filled in accordance with changesin refrigerant pressure and the time required for draining or fillingthe condenser is significant.

Another method previously used to control the outlet pressure from therefrigeration compressor has included dividing the refrigerant flowemitted from the compressor between at least two separate condensers inaccordance with the pressure at the outlet of the compressor. Sucharrangements require cooperative valve and control means at thecompressor outlet to control the quantity of compressed refrigerantflowing to the selected condensers. Such refrigerant flow control is notdirectly and rapidly responsive to change in condenser pressure ortemperature at the condenser outlet nor do such systems provide means tocont-r01 the quality or flow rate of refrigerant supplied to theexpansion device.

Summary of the invention It has been recognized that the presentinvention provides a straightforward, inexpensive condenser andcondenser control arrangement for use in a closed fluid circuit toefliciently control the condition of vaporizablecondensible Workingfluid emitted from a condenser in response to changes in the conditionof the working fluid at the condenser outlet. Moreover, the presentinvention provides a straightforward refrigerant control arrangementwith a minimum number of moving parts to simultaneously sense thecondition of the refrigerant at the condenser outlet and control therefrigerant flow rate and effective condensing area without complicatedinterrelated valve and control apparatus.

Furthermore, it has been recognized that the present invention providesa valve arrangement which not only improves the operability of thesystem and uniformly controls the quality of the refrigerant supplied tothe expansion device but also simultaneously maintains the refrigerantpressure at the compressor outlet pressure Within selected limits.

It has been further recognized that the present invention provides acondenser arrangement which can be applied in fluid flow circuits of thegeneral type where a vaporizablecondensible Working fluid is condensedand it is desirable to control the pressure within a selected portion ofthe circuit, the rate of condensation of working fluid and/or thecondition of the working fluid at the outlet of the condenser. Forexample, an advantageous condenser arrangement in accordance with thepresent invention can be used to control the condition of Working fluidemitted from a condenser in an air heating apparatus where heatedvaporizable-condensible working fluid is circulated through a fluid flowcircuit and is provided to a condenser to heat a stream of air.

Various other features of the present invention will become obvious toone skilled in the art upon reading the disclosure set forthhereinafter.

More particularly, in a heat exchange fluid flow circuit where avaporizable-condensible working fluid is circulated through a circuitincluding means to alternately vaporize and condense the fluid, thepresent invention provides an improved condenser arrangement comprising:condenser means having at least two separate flow conduits to conductworking fluid through the condenser, each conduit having an inlet tocommunicate with means to vaporize said working fluid, and a workingfluid outlet; valve means including an elongate casing havin a workingfluid outlet and Working fluid inlet ports communicatively connected tooutlets of selected flow conduits of said condenser; piston means tomove longitudinally through the casing to close selected working fluidinlet ports; and, means to move the piston in the casing to control suchselected Working fluid inlets in response to condition of working fluidadmitted to the casing from the condensing means.

It will be appreciated by those skilled in the art that various changescan be made in the arrangement, construction or form of the condenserarrangement disclosed herein without departing from the scope or spiritof the present invention.

Brief description of. the drawings Referring now to the drawings whichshow one arrangement and adaptations thereof in accordance with thepresent invention:

FIGURE 1 is a diagrammatic view of a refrigeration system including oneexample of a condenser arrangement in accordance with the presentinvention;

FIGURE 2 is a diagrammatic view of a fluid heater apparatus includingone example of a condenser arrangement in accordance with the presentinvention;

FIGURE 3 is a view, in section, showing an example of apressure-responsive valve which can be used in a condenser arrangementin accordance with the present invention; and,

FIGURE 4 is a view, in section, showing an example of atemperature-responsive valve arrangement which can be used in acondenser arrangement in accordance with the present invention.

Description of example embodiments of the invention FIGURE 1 shows acondenser 2 and valve 3, in accordance with the present invention,provided in an example of a flow circuit including a compressor 1,refrigeration expansion valve 4 and an evaporator 5 located in a spaceto be conditioned. In operation of the refrigeration system as shown inFIGURE 1 refrigerant is pumped from the outlet of compressor 1 tomanifold 8 and the compressed refrigerant fiows through the selectivelyopen conduits of condenser 2 so at least a part of the refrigerant iscondensed and the condensed refrigerant is supplied to an expansiondevice 4. In accordance with one feature of the present invention anarrangement is provided to simultaneously regulate the refrigerant flowrate and condensing area so the pressure of the refrigerant supplied toexpansion valve 4 is relatively constant and the cooling capacity of therefrigeration system is relatively unaffected by conditions prevailingin the cooling medium supplied to the condenser.

Condenser 2 includes an inlet manifold 8 to receive compressedrefrigerant from the outlet of the compressor by means of a conduit 7.In accordance with one feature of the present invention, condenser 2includes at least two separate flow conduits, and in the example ofFIGURE 1 four separate flow conduits 9, 11, 12, and 13 are provided.Each conduit has an inlet communicating with manifold 8 and a separateoutlet connected to valve 3 as hereinafter described.

A conduit is provided to connect outlet 14 of valve 3 with an expansiondevice 4 to provide expanded cooled refrigerant to an evaporator coil 5located in space 6 to be served by the refrigeration system. Refrigerantis returned from evaporator 5 to the inlet of compressor 1 by means of arefrigerant return conduit 17.

FIGURE 3 is a view, in section, of one example of a valve 3 which can beused in a condenser arrangement in accordance with the present inventionand includes an elongate outer casing 10 having refrigerant inlet ports9a, 11a, 12a, and 13a, in longitudinally spaced relation in the side ofthe casing. In accordance with one feature of i the present invention,each of the inlets ports 3a, 11a, 12a,

and 13a is connected to the outlet of a separate conduit of condenser 2,for example conduits 9, 11, 12, and 13 respectively.

A piston 21 is cooperatively adapted to move in longitudinal slidingrelation within casing 10 to advantageously control the opening andclosing of a number of the inlet ports and divide casing 10 intochambers 27 and 28 on either side of the piston in accordance with theposition of the piston in casing 10. Chamber 3% can be provided toreceive piSton 21 under selected conditions so none of the inlet portsare covered and closed and in response to a selected change in conditionof refrigerant piston 21 can move freely out of chamber 28 to coverselected inlet ports. In the example of FIGURE 3, piston 21 canadvantageously be long enough to cover only inlet ports 9:1, 11a, 12aand a stop 20 can be disposed as shown, in casing 10 to restrict themovement of piston 21 so inlet 13a is never closed and a minimumrefrigerant flow is assured.

Piston 21 can be of a straightforward construction using a cylindricalsection of selected length dependent on the spacing between inlet ports9a, 11a, 12a, 13a, and the number of such ports to be open or closed atany one time. In the example of FIGURE 3, piston 21 includes machined orrolled circumferential grooves (not shown) for receiving O-rings 22 ofsuitable materials, for example Teflon, to restrict leakage ofcompressed refrigerant past piston 21.

Piston 21 advantageously moves freel in casing 10 as hereinbeforedescribed to close or open selected compressed refrigerant ports inaccordance with the disposi tion of the inlet ports and the position ofpiston 21 in casing 10. Means, for example a spring 23, can be providedto maintain selected force on one end of piston 21. In the example asshown in FIGURE 3, spring 23 can be a compression spring where the forceexerted by the spring varies with the extent of compression of thespring to provide a variable force on one side of piston 21 andadvantageously urge piston 21 through housing 10 toward refrigerantoutlet 14 of casing 10.

A gas bleed outlet 16 can be provided from chamber 28 for the escape ofthe compressed refrigerant which leaks past piston 21. A pressureresponsive relief valve 16a can be provided at outlet 16 to control therate at which refrigerant escapes from chamber 28 to provide arelatively constant back pressure within chamber 28 so movement ofpiston 21 through casing 10 is unaffected by the rate at whichrefrigerant leaks past piston 21.

When a pressure responsive valve as shown in FIGURE 3 is used in arefrigerant circuit as shown in FIGURE 1, refrigerant entering chamber27 exerts a force on the other end of piston 21 to urge the piston in adirection to compress spring 23 and open inlet ports where the forceexerted by the spring increases with increased refrigerant pressure sothe piston assumes balanced position in casing 10 dependent on thepressure of the refrigerant entering chamber 27. Selection of amechanical spring means 23 with known loading characteristics providesan arrangement where the piston will move to a prescribed position incasing 10 in response to selected refrigerant pressure in chamber 27 andwill respond predictably to change in pressure of the refrigerant toopen or close refrigerant inlets 9a, 11a, and 12a. For example, as thepressure of the compressed refrigerant emitted from condenser 2 isdecreased, the force exerted on the end of piston 21 by the fluidentering chamber 27 is diminished, so the piston 21 moves in casing 10in response to the force of spring 23 to cover additional refrigerantinlet ports and shut off the flow of refrigerant through thecorresponding conduits of condenser 2. On the contrary, when thepressure in condenser 2 is increased, piston 21 is urged in an oppositedirection to open additional conduits through condenser 2 to increasethe flow of refrigerant. It will be noted that as additional conduitsare opened in response to increased refrigerant pressure, the pressuredrop through the condenser is decreased and the condensing area ofcondenser 2 is simultaneously increased to provide additional heattransfer area so the refrigerant is cooled to decrease the refrigerantpressure at the outlet some respects similar to the pressure responsivevalve as shown in FIGURE 3 in that it includes an elongate outer casing1011 having longitudinally spaced inlet ports 9b, 11b and 13b where eachinlet port communicates with conduits 11, 12, and 13 respectively, ofcondenser 2. A piston 31 is adapted to move through casing 10a to closeor open selected number of inlet ports and divide casing 10 intochambers 37 and 38 where chamber 38 is adapted to receive piston 31under selected conditions so that none of the inlet ports are closed.

Piston 31 can be of selected length to block a selected number of inletports and, as in the example of the valve of FIGURE 3, piston 31 is longenough to cover ports 9b, 11b, and 12b. Also, as in the example of thevalve of FIGURE 3, a stop 36 can be provided in casing 10 to preventpiston 31 from blocking all of the inlet ports to completely stop theflow of refrigeration through condenser 2.

Piston 31 is similar to piston 21 of FIGURE 3 and can be ofstraightforward construction using a cylindrical section with groovesmachined or rolled for receiving 0- rings 32 of a suitable material, forexample Teflon. 0- rings 32 are provided to restrict flow of refrigerantpast piston 31, but a small amount of leakage is likely to occur sobleed port 16 can be provided and is connected to the inlet ofcompressor 1 by means of conduit 18. It is desirable to provide gasbleed means such as outlet 16 and conduit 18 even if no refrigerantleaks past piston 31 because movement of piston 31 causes relatedexpansion and contraction of chambers 37 and 38 and the gas flowresulting from change in chamber must be accommodated without affectingthe movement of the piston. Since a small amount of refrigerant leakagecan be ac commodated and O-ring seals can be used, the relative machinetolerance for piston 31 and valve casing 10 are not restrictive and thepiston can be adapted to move freely through casing 10.

In the example of a valve 3 as shown in FIGURE 4, piston 31 can be movedin casing 14) by a temperature responsive actuator 34, for example atemperature responsive actuator manufactured under the trade name Elacby Standard-Thompson Company, where a change in the temperature ofrefrigerant entering the valve causes a change in linear dimension ofthe actuator to move the piston. Actuator 34 is supported in casing 10by mounting block 37 and piston 31 can be fastened to actuator 34 or, asshown in the example of FIGURE 3, piston 31 can merely rest on actuator34. The Elac temperature responsive actuator of the example of FIGURE 4includes a piston 34a which is forced from housing 34b in response to anincrease in temperature. The housing can include a substance having ahigh coeflicient of thermal expansion to obtain a significant movementof piston 34a with relatively little change in temperature. Sometemperature responsive actuators, for example the actuator where piston34b is filled with material having high coefficient of thermalexpansion, do not provide means to return the piston to the housing inresponse to decreased temperature, so a spring 33 can be provided tosupply the return force necessary to simultaneously reposition bothpiston 34a in housing 34 and piston 31 in casing 10. As distinguishedfrom spring 23 of the embodiment of FIGURE 3 which advantageously causesmovement of piston 21, spring 33 prevents any movement of piston 31 incasing 10a in response to change in refrigerant pressure in chamber 37.In a valve as shown in the example of FIGURE 4 where the piston movementis controlled by thermal element 34 and restricted by a spring 33 it isnot necessary to provide absolute control of the gas pressure in chamber38 on the inactive side of the piston because the actuator is responsiveto temperature and provides a significant operating force to overcome aslight imbalance in gas pressure across the piston. However, asdiscussed previously means, for example a bleed 16, can be provided toprevent the build-up of significant gas pressure or vacuum in chamber 38which, if uncontrolled, could develop sufficient force to adverselyaffect the responsiveness of the piston 31 to change in temperature ofrefrigerant entering casing 10a.

In the refrigeration system as shown in FIGURE 1, which can include avalve as shown in the example of FIGURE 4, the flow of refrigerantthrough condenser 2 is controlled by temperature of the refrigerantemitted from condenser 2. It will be noted that the temperature of therefrigerant emitted from condenser 2 decreases with a decrease intemperature of cooling medium for example air, supplied to condenser 2or with a decrease in the temperature of refrigerant emitted fromcompressor 1. A decrease in refrigerant temperature is sensed by thermalresponsive element 34 of valve 3 and the element permits withdrawal ofpiston 31 in casing 10a to close additional inlet ports in casing 10a.The flow of refrigerant through condenser 2 is thereby restricted so theoutlet pressure of compressor 1 is increased and the effectivecondensing area of condenser 2 is decreased so the temperature and thepressure of the refrigerant emitted from condenser 2 are increased. Onthe other hand as the refrigerant temperature is increased, temperatureresponsive element 34 expands and piston 31 is moved in an oppositedirection in casing 10a to open additional flow conduits of condenser 2to increase the flow of refrigerant from compressor 1 and decrease thepressure and temperature of the refrigerant.

As stated hereinbefore, the arrangement in accordance with the presentinvention can be used in any application where a working fluid isvaporized and condensed in a fluid flow circuit. FIGURE 2 is a schematicdiagram of an air heating device including a condenser arrangement inaccordance with the present invention. The heater illustrated in FIGURE2 includes a vaporized working fluid generator 41 having an integralheat source and a boiler to provide vaporized working fluid at selectedpressure. The air heating device can further include a fluid responsiveengine 42 driven by pressurized working fluid emitted from generator 41as hereinafter described. In accordance with the present invention,condenser 40 receives heated working fluid and transfers the heat to theair passed through condenser 40 in heat exchange relation.

The heater as shown in the example of FIGURE 2 is self-powered so anauxiliary source of power, other than vaporized fluid generator 41, isnot necessary. The selfpowered air heater as shown in FIGURE 2 includesa power transmitting device 43 which receives power from engine 42 todrive several auxiliary elements including a combustion air blower 44,fan device 47, a motive fluid feed pump 53, and a fuel pump 48. Each ofthe elements can be drivingly connected to power transmitting means 43,for example by drive shaft 44a, 47a, 48a, and 53a respectively.

Combustion air blower 44 is provided to supply combustion air to theheat source included in vapor generator 41 and fan 47 is provided tomove the stream of air to be heated through condenser 40. Pump 53 isprovided to return condensed fluid from receiver 54 to vapor generator41 and fuel to be burned in working fluid generator 41 can be providedby means of a pump 48 where the fuel is delivered to inlet 52 from astorage source (not shown). It is to be noted that a fuel control v lve49 can be provided to control fuel flow to vapor generator 41 inresponse to selected conditions, for example, the temperature of the airemitted from condenser 40 as measured by thermal element 51 and acondenser arrangement provided by the present invention can be used tocontrol working fluid pressure and temperature. It will be noted thatthe rate of feed of fuel to working fluid generator 51 determines therate of vaporization of fluid at selected pressure, and the quantity ofheat available to heat fluid passing through condenser 40.

As previously discussed, engine 42 receives vaporized motive fluid fromgenerator 41 to transform a portion of the pressure energy of theworking fluid to rotary motion to drive power transmitting means 43.Reduced pressure motive fluid is exhausted from engine 42 to condenser40. A portion of the vaporized motive fluid from generator 41 can beby-passed around engine 42 through by-pass 45 to maintain a constantdifferential pressure across engine 42 to selectively control poweroutput from engine 42 where by-pass 45 includes pressure responsivevalve 46 to control the differential pressure across turbine 42 and thepressure at the outlet of generator 41. The fluid which is by-passedaround engine 42 and the fluid passed through engine 42 are recombinedto flow to condenser 40 to impart heat to air passed through condenser40 in heat exchange relation. Flow of motive fluid from condenser 40 iscontrolled by valve 3 and the fluid is returned to receiver 54 to berecycled to generator 41.

As explained hereinbefore with reference to the example of FIGURE 1,condenser 40 of the heater of FIGURE 2 can include a number of separateflow conduits, for example 9c, 11c, 12c, and 130 where each separateconduit can be connected to valve 3 through separate inlet ports. If apressure responsive valve as illustrated in FIGURE 3 is used, anincrease in pressure of the fluid in chamber 27 of casing indicatesincreased fluid pressure in condenser 40 which can, for example, be theresult of reduced rate of condensation of working fluid. The reducedrate of condensation of working fluid can result from several factorsincluding an increase in the temperature of the air supplied to thecondenser to be heated without a corresponding change in the rate offeed of fuel to generator 41 as hereinbefore described. The presentinvention advantageously provides an arrangement to maintain workingfluid pressure in such air heating devices to promote stable operationswhile fuel feed rate corrections are made. In response to an increase inworking fluid pressure, piston 21 of valve 3 moves to open additionalconduits through condenser 40 to increase effective heat transfer areaand the rate of condensation of fluid in condenser 40. Likewise,decreased fluid pressure resulting from increased rate of condensation,which can result from decreased temperature of the air passing overcondenser 40, causes valve 3 to close to decrease heat transfer area andincrease working fluid pressure. In the application as illustrated inFIGURE 2 valve 3 can be either pressure or temperature responsive andcan advantageously be adjusted to maintain selected refrigerantconditions, for example, complete condensation of motive fluid incondenser 40, or a constant downstream pressure at the outlet ofcondenser 40.

The invention claimed is:

1. In a heat exchange fluid flow circuit where a vaporizable-condensibleworking fluid is circulated through the circuit to be alternatelyvaporized and condensed, an improved working fluid condenser arrangementcomprising: a source of vaporized working fluid; condenser means havingat least two separate flow conduits to conduct working fluid through thecondenser, each conduit having an inlet to communicate with the sourceof working fluid and a working fluid outlet; valve means including anelongate casing having working fluid means and Working fluid inlet portsspaced longitudinally along a portion of the length of said casing witheach port communicatively connected to the outlet of a selected flowconduit of said condenser; piston means cooperatively disposed withinsaid casing to move longitudinally through said casing to close selectedworking fluid inlet ports to define first chamber means on one side ofsaid piston means and second chamber means on the other side of saidpiston means where said inlet ports and said outlet means are incommunicative relation with said second chamber means; and, workingfluid temperature responsive means disposed in said second chamber tomove said piston in said casing to open and close selected working fluidinlet ports in response to change in temperature of working fluidadmitted to said casing from said condenser means.

2. The apparatus of claim 1 wherein said casing includes working fluidescape means communicatively connected with said first chamber toprevent entrapment of working fluid in said first chamber to restrictmovement of said piston means.

3. The apparatus of claim 2 wherein said elongate casing means includespiston stop means cooperatively disposed in said second chamber toprevent said piston means from closing all of said working fluid inletports.

4. In a closed refrigeration circuit through which avaporizable-condensible refrigerant is circulated to cause a coolingeffect, the circuit including a refrigerant compressor to compressrefrigerant and pump such refrigerant through said circuit, condensermeans to receive compressed refrigerant from said compressor means tocondense said refrigerant, expansion means to receive compressed,condensed refrigerant from said condenser means to expand saidrefrigerant, and evaporator means to receive expanded cooled refrigerantfrom said expansion means to provide a cooling effect to a selectedlocation, the present invention provides an improved condensingarrangement comprising: condenser means having at least two separateflow conduits to conduct refrigerant to said condenser, each conduithaving an inlet to communicate with the high pressure outlet side ofsaid compressor and a working fluid outlet; valve means including anelongate casing having a working fluid outlet adjacent one end of saidvalve means and working fluid inlet ports spaced longitudinally alongsaid casing; each such inlet communicatively connected to an outlet of'working fluid conduit of said condenser; piston means to movelongitudinally within said casing to and define a first chamber betweensaid casing and one end of said piston means and a second chamberbetween said casing and a second end of said casing where said secondchamber is in communicative relation with said working fluid outlet fromsaid casing and said fluid inlet ports; and means to move said piston insaid casing to open and close selected working fluid inlet ports inresponse to change in temperature of the working fluid admittted to thecasing from the condenser means.

References Cited UNITED STATES PATENTS 3,323,318 6/1967 Fisher 62l96MEYER PERLIN, Primary Examiner.

U.S. Cl. X.R. 6250 l37602

